Loop Habit Tracker Review 2026: Free, Fast, Solo

Loop Habit Tracker is a free, open source (GPLv3) Android habit tracker that holds a 4.7 rating from 63,197 ratings and over 5 million downloads on Google Play, read on 7 September 2026. It has no ads, no paid tier and no account, because it has no server: its Android manifest declares five permissions and the internet permission is not one of them, so cloud sync, sharing and accountability features are impossible by construction rather than merely absent. Its headline feature is the habit score, which the app describes as an advanced formula without publishing it. The source file does: the score is an exponential moving average whose daily multiplier is 0.5 raised to the power of the square root of the habit frequency divided by 13. For a daily habit that gives a 13-day half-life, so one missed day drops a perfect score to 94.8 percent instead of resetting it, and reaching 90 percent takes 44 straight days. Loop is the best free choice if you use Android, track alone and want your data on your device. It is the wrong choice if you use an iPhone, want the same data on two devices, or need another person to notice when you stop.

Loop Habit Tracker is the app people recommend when someone asks for a free habit tracker with no catch, and the recommendation is fair: no ads, no subscription, no account, no upsell. What almost nobody explains is the thing the app is actually built around. Its habit score is described on the project page as an advanced formula, and the formula itself is never published anywhere except in one file of the source code. We read that file, ran the numbers, and it turns out to explain both why Loop feels forgiving and why it can never do the one thing a lot of people install a tracker for.

Is Loop Habit Tracker worth using in 2026?

Yes, if you use Android, track your habits alone, and want your data to stay on your phone. No, in every other case. That is a narrow recommendation for an app rated 4.7 out of 5 from 63,197 ratings with over 5 million downloads, but the narrowness is the point. Loop is not a stripped-down version of a bigger product with features held back behind a paywall. There is no paywall and no server, so what it does not do, it cannot do.

How does Loop actually calculate your habit score?

Loop’s habit score is an exponential moving average: each day your previous score is multiplied by 0.5 raised to the power of the square root of the habit frequency divided by 13, and the day’s result is added with whatever weight is left over. That single line, from Score.kt in the project repository, is the whole mechanism. For a daily habit the frequency is 1, so the multiplier is 0.9481 and the half-life is exactly 13 days. For a habit set to three times a week the frequency is 3 divided by 7, and the half-life stretches to about 20 days. The general form is neat enough to write out: the half-life in days is 13 divided by the square root of the frequency.

Run that forward and the app’s behaviour stops being mysterious. Starting from zero and never missing, a daily habit reaches 50 percent on day 13, 79.8 percent on day 30, 90.4 percent on day 44 and 99 percent on day 87. Run it the other way from a perfect score and one missed day costs you 5.2 points, three missed days cost 14.8, and it takes 13 days away from the habit to lose half of what you built.

One coincidence is worth flagging without overclaiming it. A perfect daily run hits 97 percent on day 66, and 66 days is the median time to automaticity in the study by Lally and colleagues at University College London, published in 2010. The repository does not document any research basis for the constant 13, so we are not going to tell you the two were connected. It does mean the curve on your screen tops out at roughly the point where the research says the behaviour has become automatic, which is a more sensible pacing than a streak counter that rewards day 400 the same way it rewards day 4.

Can you use Loop Habit Tracker on iPhone, PC or the web?

No. Loop is Android only, and the project publishes to exactly two places: Google Play and F-Droid. This matters more than a normal platform footnote, because searches for Loop on iOS, Windows, PC and the web are among the most common things people type after the app’s name. There are apps on the App Store with near-identical names, including one called Loop Habit Tracker with an asterisk, published in May 2025 by a different developer, and one called Loop: Habit Tracker published in July 2026 by another. Neither comes from the iSoron project, so installing them does not get you this app or its data format.

The demand is not hypothetical, and it is measurable in the project itself. On 7 September 2026 the tracker had 39 open issues carrying 386 reactions between them. Three issues account for 332 of those, or 86 percent.

The three things Loop’s own users have asked for longest are the three things it still does not do.

None of this is a scandal. A volunteer project is allowed to stay focused, and staying local is exactly what keeps Loop free and private. It is simply the information you need before you build two years of history into an app that lives on one phone.

Does Loop have any sharing or accountability features?

None, and the reason is verifiable in one file rather than a matter of opinion. Loop’s Android manifest declares five permissions: post notifications, receive boot completed, schedule exact alarm, use exact alarm and vibrate. The internet permission is not there. An Android app without it cannot open a network connection, which rules out cloud backup, cross-device sync, friend lists, shared streaks and every other feature that needs a second person to see your data. The Play listing’s data safety section is consistent with that: no data shared with third parties.

For a lot of people that is the whole appeal, and the honest position is that it is a real feature rather than a gap. It is also a specific trade-off. If the reason your last three habits failed is that nobody ever noticed you stopped, a tracker that cannot tell anyone is solving a different problem from yours. That is the same split we found comparing habit trackers with a social layer and reviewing accountability apps: the solo tools are usually better built, and the social ones are usually the ones people stick with longer.

Is Loop Habit Tracker still being updated?

Yes, but the released app and the code are on different clocks. Version 2.3.1 shipped in August 2025 and the Play listing gives 15 September 2025 as its last update, so the app you install today is a year old. The repository is more active than that: commits continue through 21 July 2026, and the unreleased section of the changelog already lists habit search, archive actions from the statistics page, automatic backups to a folder you choose, and a migration of the core to Kotlin Multiplatform. That last item is the groundwork the multiplatform request would need.

Read that how you like. The project has 10,220 stars and is not abandoned, but a yearly release cadence on a volunteer project means the answer to any missing feature is measured in years, and the two headline requests have been open for five and seven.

Who Loop is right for, and where StellarHabit fits

Install Loop if you are on Android, you track alone, and local data matters to you. It is the best free option in that shape and nothing here changes that. The interface is fast, the widgets are good, the export is honest CSV and SQLite, and it will never ask you for money or an email address.

StellarHabit exists for the case Loop deliberately does not cover. It runs in the browser, so the same account opens on your phone and your laptop with nothing to install and no app store involved. It replaces the streak with a consistency percentage, for the same reason Loop’s score decays gently rather than resetting: one missed Tuesday should cost a few points, not eleven weeks of progress. And it puts that percentage in front of a small group, so that someone actually notices when it starts falling.

Our limits, in the same detail we applied to Loop. There is no money at stake, so if you need a financial penalty to move, this is not it. It is built around a group, so if you want a private tracker nobody else can see, Loop is a better fit than we are. And your data lives on our server rather than on your device, which is the direct cost of the sync and the sharing. If those trade-offs are wrong for you, keep Loop, and read how long habit formation actually takes so the number on the screen makes sense while you wait for it.